“We’ve surveyed the Earth in many different ways, from land, air and space – it’s exciting that discoveries like these are still possible,” said Dr Joe MacGregor, a Nasa glaciologist who contributed to the discovery of both Greenland craters.

The only other circular structure that the scientists think could have caused a crater of this size would be a collapsed volcano – but the closest known areas of volcanic activity are hundreds of miles away.

If they can confirm the structure is the result of a meteorite impact, it would be the 22nd largest impact crater ever found on this planet.